please help. i dont know how to solve but correct answer is $255 F. will up vote for your help :)

A manufacturing company that has only one product has established the following standards for its variable manufacturing overhead. The company bases its variable manufacturing overhead standards on direct labor-hours: Standard hours per unit of output 7.2 direct labor-hours standard variable overhead rate $14.20 per direct labor-hour The following data pertain to operations for the last month: Actual direct labor-hours Actual total variable manufacturing overhead cost Actual output 5,100 direet 1 abor-hours $72,165 600 units What is the variable overhead rate variance for the month